|Publication number||US4022384 A|
|Application number||US 05/638,964|
|Publication date||May 10, 1977|
|Filing date||Dec 8, 1975|
|Priority date||Dec 8, 1975|
|Publication number||05638964, 638964, US 4022384 A, US 4022384A, US-A-4022384, US4022384 A, US4022384A|
|Inventors||Wallis I. Hoyle, John D. Schmunk|
|Original Assignee||Hancor, Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (6), Referenced by (45), Classifications (6), Legal Events (4)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This invention relates to irrigation drip or trickle tubing. In recent years, irrigation drip tubing has become popular to increase agricultural yields. Accurate watering of the root areas of plants causes an improved growth rate and the lack of watering between plants reduces weeds. Concentrated irrigation also gives maximum utilization of available water, and the tubing itself can be used to meter liquid fertilizers, pesticides and soil conditioners.
The basic concept of irrigation tubing is sound but the design of the tubing should meet certain practical criteria. Because plants may be spaced unevenly, it is often highly desirable to have a variable means for determining the location of the outlet apertures and the flow therethrough. That is, the outlets of the irrigation tubing should be available on a basis of need rather than on any predetermined manufactured spacing. Maturing young orchards are a specific example of a crop that may require additional outlets in irrigation tubing over a period of time.
It is also highly desirable to provide a pressure reduction means within the tubing in order to permit the water to drip out at a predetermined rate regardless of the outlet aperture size. Insects have been known to enlarge outlet apertures in irrigation tubing by chewing the edges thereof. Alternately, impurities in the water may also reduce the outlet sizes. If the drip rate is dependent on outlet size, undesirably high flow rates result. Drip irrigation tubing should also be economical to manufacture, soundly designed and easy to put into operation. For example, large appendages extending from the tubing should be avoided as should any design requiring hand assembly.
Previous irrigation tubing has attempted to satisfy the requirements involved but have been deficient in some respect. For example, some outlet openings on prior art tubing are placed in a tubular member at the time the tubing is put into operation in the field. This field operation is time consuming and carelessness could cause water to enter the field at a higher or lower rate than desired and in the wrong location. The size of the outlet opening is not adequately uncontrollable and the resulting flow rates may differ considerably.
In systems where the irrigation drip holes in the outer tubular member are made at the time of manufacture, irrigation occurs uniformly along the entire length of the tubing. Thus, where plants are not evenly distributed, water is used unnecessarily. Many irrigation systems also use the size of the outlet aperture to control flow rate and encounter the above-noted insect problem.
This invention has the advantage of variable flow rates at a given location. The use of a plurality of removable bosses over outlet apertures allows irrigation only where desired and at different rates. The design and size of the tortuous path of this invention and not the sizes of the inlet or outlet aperture are used to govern the flow rate. Insect damage to or accidental enlargement of the outlet apertures does not vary the flow. A particular feature of this invention is the use of closely spaced paired outlet apertures fed by separate oppositely directed passageways. The outlet flow rate may thus be adjusted by a factor of two and, alternately, one aperture may be reserved in case the other one clogs. A separate inlet aperture is used to feed each passageway and thus isolates any obstruction. This tubing is also economical to manufacture and put into operation. No special hand fitting is required.
An irrigation tubing comprising an outer tubular member having an inside wall, an outside wall and outlet apertures therethrough. An inner tubular member fits inside the outer tubular member and has a repeating pattern of crests and roots. The crests engage the inside wall of the outer tubular member, and the roots form connected conduits defining a tortuous passageway which reduces the pressure of liquid traveling therein. Apertures in the inner tubular member provide for fluid communication between the inside of the inner tubular member and the passageway.
FIG. 1 is a perspective view of the irrigation tubing of this invention;
FIG. 2 is a side view of the tubing with the outer tubular member partially removed;
FIG. 3 is a plan view of a section of one side of the irrigation tubing with the outer tubular member partially removed;
FIG. 4 is a section 4--4 taken through FIG. 3; and
FIGS. 5 through 9 illustrate tortuous paths utilized on the inner tubular member.
As illustrated in FIGS. 1 through 4, a repetitive pattern of irrigation drip tubing 10 includes an outer tubular member 12 having a substantially circular cross-section and outlet bosses 14 and 15 at repetitive periodic intervals. Different shapes of the outer tubular member will be obvious to one skilled in the art. It is only necessary to have some combination of corrugated and/or smooth layers that can result in a continuous passageway for the fluid. The pair of outlet bosses 14 and 15 are spaced about 18 inches from the previous bosses 16 and 17. The bosses may be any type of removable element which covers an outlet aperture 18. Normally, the bosses 14 and 15 will be centrally located between inlets as discussed hereinafter. However, it is fully anticipated that a series of bosses or apertures may be located along the length of the tubing to provide maximum flexibility in the choice of outlets and the flow emanating therefrom. Those outlets closer to the inlet apertures will have a higher pressure and greater flow. The individual bosses 14 and 15 are spaced by one completely circumferential crest 15a which acts as a seal between them. The bosses are formed during the process of manufacture and may have various sized diameters, but 0.080 inches has been found to work satisfactorily. As noted earlier, the size of the inlet and outlet apertures is not critical to the determination of the flow rate which may vary from 0.25 to 8 gallons per hour. One gallon per hour is common using a passageway length of travel about 200 inches or a tubing length of 9 inches.
The outer tubular member 12 will vary according to the size of irrigation drip tubing desired. The range of sizes will be about 1/4 inch to 11/2 inches having a wall thickness of about 0.005 to 0.06 inches and averages about 0.020 inches. The material used in the outer tubular member as well as the inner tubular member may be polyethylene, polypropylene, polybutene, polyvinylchloride, thermoplastics, elastomers, copolymers and other material and synthetic resins, polyester resins and laminates. The material must be such that it will resist ultraviolet degradation, heat, chemicals and moisture found in its environment.
An inner tubular member 19 includes crests 20 and roots 21 which form a series of connected conduits 22 forming passageways 26 and 28 (FIG. 5) extending the length of the tubing. The shape of the conduits can take many forms but a square configuration has proven useful. The sizes of the conduits 22 may vary from about 0.015 to 0.125 inches square but 0.055 inches square have been found to work satisfactorily. Inlet apertures 23 and 24, about 0.080 inches in diameter, provide openings for water on the inside of the inner tubular member to enter the passageways 26 and 28. The size of the inlet apertures may vary. Lands 29 and 30 optionally surround the apertures 23 and 24 and act as the channeling means for directing the water as shown by the arrows in FIG. 2 into the conduits which combine to form passageways. A pair of inlets are located about every 18 inches along the tubing. This distance is variable with the size of the conduits, the length of the tubing and the pressure drop desired. A longitudinal crest 31 (FIG. 3) along the length of the inner tubular member engages the inside wall of the outer tubular member 12. The crest 31 prevents any water from moving between conduits 22 except through the passageway formed by the crests and roots. There are different possible passageway designs. As illustrated in FIG. 5, the passageways 26 and 28 in the preferred embodiment include circumferentially extending parallel conduits connected to alternating ends thereof to form a reversing passageway from the apertures 23 and 24. The passageways 26 and 28 are separated by a crest 15a (FIG. 5).
FIG. 6 shows an alternate embodiment of FIG. 5 wherein circumferentially and longitudinally extending parallel conduits 30 are connected at alternating ends thereof to provide a reversing passageway 32. The alternate embodiment of FIG. 6 provides a passageway 32 that is longer than that of FIG. 5 for the same linear length of tubing and will cause a greater reduction in flow rates.
FIG. 7 shows longitudinally extending parallel conduits 34 connected at alternating ends 36 to form a reversing passageway 38 along the length of the tubing. The specie shown in FIG. 8 includes circumferentially and longitudinally extending conduits forming a sawtooth passageway 40 having other conduits 42 and 44 parallel and having the end of each adjacent conduit 44 and 45 connected.
FIG. 9 illustrates an alternate embodiment wherein the tortuous passageway 46 is formed of conduits 48 in a type of swirl effect and includes a series of conduits 50 and 52 which are parallel to each other and reverse several times.
Whatever passageway design is used, there are definite advantages to the use of a pair of spaced inlet apertures feeding oppositely directed passageways to closely spaced outlet bosses. Each closely spaced pair of outlets are fed by inlet apertures usually, but not necessarily separated by about 18 inches which direct water from different directions. Thus, it is highly unlikely that both outlets could become clogged simultaneously. Moreover, if both outlet apertures are open, which normally is the case, the outlet flow rate can be adjusted by a factor of two or more from the rate of a single outlet aperture.
It is also anticipated that inlets and outlets may be alternated instead of paired. Other tortuous paths as well as other alterations in this invention will be obvious to one skilled in the art and those embodiments are included within the scope of this invention.
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|US3672571 *||Aug 11, 1970||Jun 27, 1972||A C I Operations||Trickle irrigation system|
|US3777987 *||Aug 4, 1972||Dec 11, 1973||Allport Davies||Irrigation device|
|US3870236 *||Mar 14, 1973||Mar 11, 1975||Sahagun Barragan Jaime||Dripping irrigation tubing|
|US3873030 *||Feb 19, 1974||Mar 25, 1975||Barragan Jaime Suhagun||One-piece drip irrigation device|
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|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4126998 *||Oct 14, 1977||Nov 28, 1978||Gideon Gilead||Irrigation apparatus|
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|U.S. Classification||239/542, 138/42, 405/43|
|Dec 10, 1982||AS||Assignment|
Owner name: NATIONAL CITY BANK, (THE AGENT)
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:HANCOR, INC., AN OH CORP.;REEL/FRAME:004076/0605
Effective date: 19821208
Owner name: NATIONAL CITY BANK, (THE AGENT), OHIO
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HANCOR, INC., AN OH CORP.;REEL/FRAME:004076/0605
Effective date: 19821208
|Mar 16, 1987||AS||Assignment|
Owner name: NAIONAL CITY BANK
Free format text: SECURITY INTEREST;ASSIGNOR:HANCOR, INC. A CORP. OF OH.;REEL/FRAME:004684/0176
Effective date: 19860422
Owner name: HANCOR, INC.
Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:NATIONAL CITY BANK, AS AGENT;REEL/FRAME:004684/0172
Effective date: 19860422
|Jul 23, 1990||AS||Assignment|
Owner name: NATIONAL CITY BANK
Free format text: SECURITY INTEREST;ASSIGNOR:HANCOR, INC., A CORP. OF OH;REEL/FRAME:005404/0116
Effective date: 19900713
|Oct 6, 1992||AS||Assignment|
Owner name: NATIONAL CITY BANK, OHIO
Free format text: SECOND AMENDED AND RESTATED COLLATERAL ASSIGNMENT OF PATENTS;ASSIGNOR:HANCOR, INC.;REEL/FRAME:006331/0651
Effective date: 19920923